Sewing machine



F. BAKER.

SEWING-MACHINE.

APPLICATION FILED ram/10.1920.

3 SHEETSSHEET l.

Patented May 23,

Zak?

FLBAKER.

SEWING MACHINE. armcmmf FILED MAYIO, 1920.

' 1,417,47 Patelited my 23,1922.

3 snms snm 3.

Arra /011". fie Zrfc 2a. 1461 UNITED STATES:

PATENT OFFICE.

FREDERICK BAKER, OF BLACKHEATH, ENGLAND, ASSIG-NOR TO CYRIL ERNEST HART,

, OF WARNFORD COURT, LONDON, ENGLAND, AND' HENRY HERBERT BUNYAN, OF

MAIDENHEAD, ENGLAND.

snwrne MACHINE.

Application filed May 10, 1920. Serial No. 380,342.

(GRANTED UNDER THE PROVISIONS or THE ACT 01* MA CH 3, 1921, 41 STAT. I.., 1313.

To all whom it may concern:

Be it known that I, FREDERICK BAKER, a subject of the King of Great Britain, residing at Blackheath, in the county of Kent, England have invented new and useful Improvements Relating to Sewing Machines (for which I have filed application in Great Britain, No. 144, filed January 2, 1919, Patent No. 165,813), of which the following is a specification.

This invention has reference to single thread sewing machines of the kind in which an angularly movable loop drawing device situated beneath the needle plate engages the needle thread at each ascent of the needle and after drawing a loop of thread disengages said loop before the bight has been carried through a semi-circle.

A machine operating on this principle embodies in its construction a stationary device situated adjacent to the loop drawing device and having means for arresting and retaining certain loops which are yieldingly retained in tension thereby while other loops are allowed to pass freely over the device.

The primary object of the present .improvements is to' provide an improved tension device which shall be capable of operating with great certainty and precision when run at the high speed necessary in sewing machines actuated by power.

A further and important object of the invention is to ensure that the long loopformed in the manner above referred to shall be retained under improved tension' as it is taken up stitch by stitch by the sewing.

Further objects are to reduce the extent of the movement of the parts and to generally improve the construction of devices of the aforesaid kindv whereby they may be rendered more eflicient to the ends in view. Vith these and such other objectsas may hereinafter appear or are incidental thereto the present inventionin its broadest aspect may be said to contemplate a construction of tension device or thread loopdetainer wherein the main loop arresting and retaining member or members is or are held substantially stationary within the tension device from the time a long loop is arrestedand retained thereby until the bight of the loop is in position for releasing.

Stated more specifically the invention is embodied in a construction wherein the aforesaidstationary tension device is pro vided with a s'lidably mounted element which is ormally held in a shrouded position within the casingof the device but is adapted at predetermined intervals to deliver from one end the bight of one loop and be slidingly moved into position,- to arrest another long loop at the oppositev end whereupon it is returned to its shrouded andloop retaining position and the cycle of operations are repeated. I j

In one embodiment of the invention the stationary casing of the device is formed with a-housing in which. is movably or slidably mounted a rod'constituting the main loop arresting and ,retainingelement said;

rod being retained in its shrouded position Specification o f LettersPate nt I "Patented May/"23, 192 2.

by a movable element which at predetermined; periods is actuated through an approprlate lever or levers operated by'a cam on the under shaft of the machine or otherwise in such a manner as to permit said rod 1 under the influence of a suitable spring for example to move longitudinally at the, proper moment to arrest a fresh long loop of thread. In the initial position of the parts one curved back of the stationary casing in such 'end of the aforesaid rod projects beyond the a manner as to arrest a long loop of needle thread after. this latter has been'drawn ofi by the loop drawing device and is being drawn up around and over the casing the bight of said loop being arrested. by passing under said rod. Meansare provided whereby when this occurs, said rod. is returned to its shrouded position and the aforesaidlong loop permitted to slide along therod stepby step as the thread is taken up by the sewing. This may be effected by providing a lever or otherapp'ropriate device adapted to be 'ac-, 1

tuated in any suitable manner to positively return the rod to the shrouded position.

As the long loop slides along the aforesaid rod until it reaches the end whereupon it becomes re 1 loop is taken up stitch by 1 stltch by thesewing the bight of said long.

leased from the rod thereby causing the 1 latter to be free to move into a loop arresting position in due time but is retained by a hook or projection carried by the aforesaid stationary casing. The bight isnow in such a position thatthe point of the needle enters same at its next descent andthe rod being 77 As hereinbefore stated theabove described-- tension device is particularly but not exclusivelyapplicable to high speed power machines. With such machines particularly when using certain grades or qualities of thread the bulging strand offered by the needle as it commences each ascent is not always well formed and in suchcircumstances andwhere the tension device is in a I lateral position with respect to the loop drawing device the bulging strand might miss being engaged and drawn along between the adjacent faces of the two devices and we therefore provide an advance loop engagerwhich enters the loop just ahead of the loop drawing portion of the loop drawing device and carries the bight across to the lower face of the'tension device ready for engagement between this faceand the adjacent face of the loop drawing device in the known manner.

In order that the invention may be clearly understood and readily carried into effect the same will now be described more fully with reference vto the accompanying draw- Figure 1 is a sectional side elevation with the inner face plate removed of one constructional form of our improved tension de I vice and Figure 1 is an .end' vlew.

Figure 2 is a plan corresponding to F igure 1. a I V Figure 3 1s a cross section on the line 33 of Flgure 1.

Figure 4 is affragmentary cross sectional view of the device showing a loop engaged thereby.

Figure 5' is similar to Figure 1 but shows the parts in a difierentpositio'n. H

Figure 6 is a sectional elevation of certain parts of the machineviewed from the end of the under shaft; the tensiondevice and the advance loop engager are shewn in full lines and the loop drawing device is shewnjin. dotted lines the latter being in fact removed to expose the other parts.

Figure 7 is a longitudinal sectional elevation ofthe parts shewn in Figure 6.

Figure 8 is a sectional elevation on the line 88 of Figure 7. r

The general operation of the machine is known by disclosure for examplev in the specifications of the British prior Patents 14661 of 1912 and 22250 of 1913 and need'not, therefore be fully described. A is the needle; Bthe loop drawing device C the undersha'ft'on which the device'B is mountthe loop drawing device and the adjacent co-operating faces of these. devices are formedfor. tongueand groove'sliding engagement so. that at each reciprocation of the needle a loop of thread is drawn outbetween the aforesaid co-operating faces and is then released in such a position that in beingdrawn up it passes around and ov sion device in the-known-ma-nner.

Referring now to the construction form of the improved tension device D constituting the main features of the present invention it is seen that this comprises the main body 1 of the casing the inner face or cover plate 2 and the movable parts arranged with in consisting of the loop arresting and retaining member in the form of a longitudinally sliding rod 3a spring controlled rod operating lever 4 a spring controlled tension block 5 on which the rod 3 is slidably mount ed a detaining member 6 and an operating lever 7 therefor. i

In Figure 1 the rod 3isin its shrouded position so that sub loops can pass unchecked around and over'the whole tension er the tendevice. A small coil spring 4 in the hub of I of obstruction to movement on the part of the rod 3. When however the lever 7 is rocked about itspivot as for example by a cam 8 on a collar 9 on the undershaft C engaging the tail of the lever 7 the member 6 is lowered as shown in Figure 5 and the rod 3 moves outwards under the action of the lever 41. The pointed outward end'of the rod 3 then projects through an aperture 11 in the back of the casing ready to engage a loop of thread as thelatter is being drawn up around and over'the casing.

The rod 3 is approximately wedge shape or triangular in cross section as seen clearly in Figure 3, and the adjacent portions of the casing are shaped to form a suitable housing for the rod. The base of the rod is preferably formed with a suitably shaped interconnecting surface cooperating with a correspondingly shaped surface on the tension block. In the construction shown the base of the rod is formed with a tongue or rib 12 and the tension block is formed with a corresponding groove. lVhen a loop has been arrested by the projecting end of the rod '3 and has been fully drawn ofi' the rod is positively returned to itsshrouded position by suitable means such as an oscillatory thereby thrust this rod into its shrouded position where it is retained by the detaining member 6 until again released. The hub of the lever 13 is provided with a spring which normally urges the lever in the direction of the arrow shown in Figure 5 so that the normal position of the free end of the lever 13 is clear of the back of the tension device.

When a loop in being drawn up around and'over, the tension device is arrested by the projecting end of the rod' 3 its bight slip over the shoulders into the main narrow gap extending along the back of the casing- The loop then occupies a position indicated roughly and enlarged in Figure 4. It is to be observed that therod as a whole has necessarily become slightly depressed in its housing to accommodate the thread and that the latter necessarily occupies a tortuous position between the tongue 12 on the rod and the groove on the tension block.

7 The thread by reason of the aforesaid tortuous position and by being pinched between thesides of the rod 3 and itshousing is under tension as it slides along the rod. It will be understood that while this loop is passing along the rod 3 and affording what may be termed a main loop, any desired number'of subsequent loops may be drawn out and passed around and over the tension device unarrested constituting what may be termed sub-loops which form lock or knotted stitches with the strands of the main loop. It will also be observed that although the detaining member 6 of the tension device is depressed at each revolution of the undershaft the rod 3 does not move into its projecting position because it is held by the:

tension and friction of the engaged loop.

In View of the fact that whereas the strands of an arrested loop lie more obliquely in the narrow aperture on the back of the casing during the early stages of travel of the loop than during its later stage the underside of the rear end of the rod 3 may be enlarged slightly as shown in Figures 1 and 5 so as to increase somewhat the tension exerted by the rod at this stage.

The main loop finally escapes from the rod 3 and is temporarily retained by a hook or projection 15 on the casing from which it is finally levered ofi by the strands of a new long loop when the latter has been drawn out I mode of operation.

through the bight of the old long loop and is being finallyformed and drawn taut on the rod 3 in the next cycle of operations.

As hereinbefore stated it is desirable in some circumstances to ensure the engaging of the bulging strand of thread at each as cent of the needle in advance of its engagement by the actual loop drawing device. One convenient form of means for this ad vance engagement will now be described. Mounted on the same small shaft 15 as the lever 13 is a second lever 16 the short arm of which engages a cam 17- on the undershaft whilstits long arm extends up-.

wards close to the loop engaging face of the disc B and is formed at its upper end with a pin or projection 18 on which is mounted a member 19 which we may term the advance loop engager. This-advance loop engager 19' is formed with a beak-2O which normally lies alongside the inner face of the tension deviceclose to the entrance of the groove 21 with which .a tongue on the loop drawing disc cooperates in the known r manner to draw out a loop. The cam 17 on the under shaft rocks the lever 16 at each rotation of the loop drawing'disc B just as i the needle is completing its descent and commencing its ascent and just prior to the passage of the gap in the loop drawing disc across the path of the needle. Consequently the bulging strand of thread at the needle is engaged by the beak 20 and. carried across to the inner face of the tension device close to the entrance of the groove 21 where its engagement by the loop drawing disc is ensured. In describin, ;-v the above details it has beenassunied that the tension devicev is located laterally with respect to the loop drawing device and this is in fact the preferred position but it will be understood that P by suitably modifying the shape and con-j structionaldetails of the device in certain respects the said device can be adapted for riding uponthe periphery of the loop draw-' ing device without involving any changeor appreciable change in its main functions and needle 'plate for drawing loops of thread from the needle and a thread loop detainer comprising a'loop arrestingand detaining member which after arresting a loop becomes shrouded and then without itself moving keeps the arrested loop under ten-" sion while the bight is being drawn towards the needle until the time of its-release.

2.'In a single thread sewing machine, the

combination with a reciprocating needle, and

the needle plate, of means located below the needle plate for drawing loops of thread from' the needle, and a thread loop detainer comprising a loop arresting and detaining member which after arresting a loop becomes shrouded and then without itself movcomprising a casing and a loop arresting and 1deta1ning member slidable therein and serv ing after arresting a loop and becoming shrouded to frictionally retard the movement of the arrested loop along it without itself moving until the time of its release. 4. In a single thread sewing machine, the combination with a reciprocating needle, and the needle plate, of means'located below the needle plate for drawing loops of thread from the needle and a thread loop detainer comprising a casing, and'two slidably interengaging elements therein oneof which after. arresting a loop becomes shrouded and then without itself moving yieldably detains the loop under frictional restraint betweenthe :two elements while its bight is being drawn towards the needle until the time of its re l needle plate for drawing loops of thread from the needle, and a thread loop detainer comprising a caslng containinga shdably mounted rod whichln one position pro ects 4Qrat one end beyond the edge of the casing to arrest a loop and; in another position remains stationary in a shrouded position while exerting africtional restraint upon the movement of the arrested loop along it. 451 a combination with a reciprocating needle, and the needle plate, of means located below the needle plate for drawing loops or thread from the needle, and a thread loop detainer comprising a casing, a rod slidably mounted therein, means for moving the rod into a position in which one end projects beyond the casing into a loop arresting position, 'means for thrusting it into a stationary ;-:shroudedposition after its projected end has arrested aloop, and means for maintaining frictional restraint between the rodand the arrestedloop as the latter slides along-the rod.

, 7. In a single thread sewing machine, the combination with areciprocating needle, andthe needle plate, of means located below theneedle plate for drawing loops of thread from the needle, and a thread loop detainer :;comprising .a casing, a rod slidably mounted 6. In a single thread sewing machine, the

therein,means for moving-the rod intoai position in which one end projects beyond the easing into a loop arresting position, means for then thrusting the rod into a stationary shrouded position, means for retaining it in that position, means for maintaining frictional restraint between the rod and the arrested loop as the latter slides along the rod,and means for allowing the rod to be again moved into aloop arresting position when the previously arrested loop has passed clear of the rod.

8. In a single thread sewing machine, the combination with a reciprocating needle,- and the needle plate, of means. located be low the needle plate for drawing loops of thread from the needle, and a thread loop detainer comprising a casing, a rod slidably mounted therein,'means for moving the rod into a position inwhich one end projects beyondthe casinginto a loop arresting position, means for thrusting it into a stationary shrouded position after its :projected end has arrested a loop,- means for maintaining frictional restraint between the rod andthe arrested loop as the latter slides along the rod, and means on the rod for exerting greater restraint upon the loop just prior to its escape from the rod than during'the earlier passage of it under frictional constraint along the. rod.

9; In a single thread sewing machine, the combination with a reciprocating needle, and theneedle plate, of means located below the needle plate, for drawing loops of thread from the needle, and a thread loop detainer comprising a casing, a loop arresting and detaining member slidable therein and serving after arresting a loop and becoming shrouded to frictionally retard the movement of the arrested loop along it without itself moving until the time of its release, and a lever periodically rockable to cause oneend tothrust the projecting end of the slidable member into a shrouded position relatively to the casing after each arrested loop is formed. a v

10. In a single thread sewing machine, the combination with a reciprocating needle, and the needle plate, of means located below the needle plate for drawing loops of thread from the needle, and a thread loop detains r comprising a casing, a loop arresting and detaining member slidable therein and serving after arresting a loop and becoming shrouded to frictionally retard the movement of the arrested loop along it without itself moving until the timeof 1ts release, a pivoted lever and means engaging one end of said lever to rock it, the other end of said lever when rocked exerting an inward and downward thrust upon the projecting end of the said slidable member to make it as sume a shrouded position.

11. Ina sewing machine, the combination with the reciprocating needle and the needle plate, of rotary means located below the needle plate for drawing loops of thread from the needle and effecting an early release of the same, a device located laterally with respect to the rotary means and around and over which the released loops are drawn, and means for engaging the needle thread slightly in advance of the rotary means at each reciprocation of the needle.

12. In a single thread sewing machine of the class described, the combination with the reciprocating needle, the needle plate, a

rotary loop drawing disc of the early re-- lease type located below the needle plate, a casing located laterally with respect to the disc, a loop arresting and detaining member mounted in said casing to arrest and yieldingly detain certain loops while allowing others to pass completely around and over the casing, and a loop engaging device rockable to enter a bulging strand of needle thread just in advance of its engagement by the rotary disk.

FREDERICK BAKER. 

